Relation between Respiratory Sinus Arrythymia and Startle Response during Predictable and Unpredictable Threat.

Area of Science:

• Psychophysiology
• Neuroscience
• Anxiety Research

Background:

• Lower respiratory sinus arrhythmia (RSA) is associated with increased aversive responding.
• Startle potentiation is a physiological indicator of aversive responses.
• Previous research shows an inverse link between RSA and startle potentiation, but hasn't differentiated stimulus predictability.

Purpose of the Study:

• To investigate the association between resting RSA and startle eye blink responses.
• To determine if this association differs for predictable versus unpredictable aversive stimuli.
• To explore implications for understanding pathological anxiety.

Main Methods:

• Measured resting RSA during a baseline phase.
• Administered a computerized startle task with predictable and unpredictable electric shock threats.
• Recorded startle eye blink responses.

Main Results:

• Lower resting RSA was associated with greater startle potentiation during unpredictable threat.
• This association was not found during predictable threat.
• Findings suggest RSA is more robustly linked to sensitivity to unpredictable threat.

Conclusions:

• Individual differences in RSA are associated with aversive responding.
• RSA may be a more sensitive indicator for heightened responses to unpredictable threats.
• Results may inform the understanding of anxiety disorders, characterized by low RSA and heightened responses to unpredictable threat.